Our Methods

We conducted underwater video surveys to characterize fish community composition in different habitats within Project GreenShores I & II. We classified the living shorelines into 5 habitat types: bare, breakwaters, restored hardened shoreline, marsh edge, and oyster reef. Additionally, we had 2 control sites to determine what the fish communities would look like if the living shorelines hadn’t been installed. The habitats at the control sites were control offshore and control hardened shoreline. A detailed description of the characteristics of each habitat can be found on the “Habitats” page. We collected videos in Fall 2023 and Spring 2024 to better understand how seasonality would affect community composition.

We deployed replicate GoPro cameras at each habitat type for the underwater video surveys. Cameras were attached to a hard base to keep them flat, with a buoy on a float line to lower and retrieve them (Figure 1, 2). For best video clarity, water depth had to be between 0.5 - 2.5 meters, and the cameras were deployed at least 20 meters apart to minimize the likelihood of seeing the same fish swim by multiple cameras. At each habitat, six cameras are dropped in succession. When each camera is dropped, the time, depth, GPS location, and unique sample number are recorded. Cameras are left recording underwater for 15 minutes. After the six cameras are dropped, a camera with a visibility pole is dropped at the deepest part of the habitat. The visibility pole has high-contrast black and white stripes to help estimate visibility distance in our videos across various habitats each day (Figure 3). Water quality measurements are taken using a handheld YSI to collect data on temperature (℃), Dissolved oxygen (mg/L), and salinity (PSU). By the time we have dropped our 6 cameras, the visibility camera, and taken our YSI readings, the first camera has been left undisturbed for about 15 minutes, so we can go along and retrieve all 6 replicate cameras.

From our fall sampling, we have collected a total of 251 videos that can be processed.
These videos comprise:

• 18 from bare habitats
• 95 from breakwaters (including shoreward side, offshore, and breakwater ends)
• 24 from living shoreline rip rap
• 49 from the marsh edge
• 21 from oyster reefs
• 22 from control offshore
• 22 from control hardened shoreline

After collection, the videos are downloaded from the cameras and processed in the lab. We skip at least the first 1 minute of each video clip, more if the boat or dropping the camera stirs up mud and blocking our view, to minimize the effect of boat disturbance during deployment of the camera on the fish community seen. We then process ten minutes of each video by carefully reviewing the video to identify any animals present, determining their species, genus, or family, and noting the time they are observed. Our results are then analyzed to determine the Frequency of Occurrence (FoO) of each species at each habitat. FoO is a simple but effective way to summarize video data, being the percentage of videos from each habitat in which each species was observed.Comparing FoO among habitats shows where different fish are more likely to be found. This process allows us to gain a better understanding of how restoration affects fish communities at Project GreenShores I & II.

From our fall sampling, we collected a total of 248 videos that can be processed. These videos comprise 18 from bare habitats, 92 from breakwaters (including shoreward side, offshore, and breakwater ends), 24 from living shoreline rip rap, 49 from the marsh edge, 21 from oyster reefs, 22 from control offshore, and 22 from control hardened shoreline.

Additional Media